Campaign Season Spending Up 75% since 2008, Study Shows

Political spending has reached astronomical levels since just September, a new study shows. Congressional candidates, political parties and outside interest groups spent an estimated $198 million on political advertising in the five weeks between Sept. 1 and Oct. 7, according to a new study from the Wesleyan Media Project -- that's a 75 percent increase from the same period in 2008, when $113 million was spent.

Spending on Senate races jumped 84 percent, with more than $114 million going toward the airing of more than 202,000 ads within that five-week span. On the House side, spending increased 65 percent to more than $83 million for more than 198,000 ads.

"Given the record spending this year, one has to wonder whether the campaigns have no-limit credit cards," Professor Travis Ridout, co-director of the Wesleyan Media Project, said in the report. "Candidate spending is up, and independent group spending is up. With all of the ads showing up on their television screens, many Americans must be thinking that it is already the first week of November."

Republicans have advantages in both party spending and interest group spending, according to the Wesleyan Media Project. Republican-leaning outside groups actually outspent Democratically-leaning groups by a margin of almost nine-to-one in those five weeks, the group says.

Among the top 10 interest group spenders, conservative groups outspent their Democratic counterparts by a margin of over 10 to one. Four of the top 10 outside groups fall into tax categories that allow them to keep their donors secret, giving credence to the Democrats' complaints that conservatives are influencing the elections with anonymous donations to outside special interest groups. Those groups were the Karl Rove-affiliated Crossroads GPS; the 60 Plus Association, a Republican-leaning senior group; the U.S. Chamber of Commerce, a Republican-leaning business lobbying organization; and the Republican-leaning Americans for Job Security.

"We continue to see evidence of large spending by non-profits that if nothing else are profiting from protections that do not require them to disclose their donors," Wesleyan Media Project's Erika Franklin Fowler said.

The top spending interest groups were the Republican Governors Association, which spent more than $11 million on more than 16,000 ads; the U.S. Chamber of Commerce, which spent more than $9 million on more than 8,000 ads; the Karl Rove-affiliated American Crossroads, which spent nearly $5.5 million on more than 7,000 ads; and Crossroads GPS, which spent nearly $5 million on more than 5,700 ads.

While spending overall increased more on the Senate side, there are more Senate seats up for grabs this year than there were in 2008.

"The increase in activity continues to be driven largely by candidates, but the interest group and party/coordinated spending difference between House and Senate races indicate that both sides believe the House is the true battleground," said Michael Franz of the Wesleyan Media Project. "Party spending is up in the House, especially if we add in coordinated spending, while the reverse is true in the Senate where party spending is way down even if we account for the significant increase in coordinated spending."

Stephanie Condon is a political reporter for CBSNews.com. You can read more of her posts here. Follow Hotsheet on Facebook and Twitter.